1. Field of Invention
This invention relates generally to tires and to tire/vehicle systems designed for four-wheeled automotive vehicles, and specifically for such systems wherein a portion of the rear tire tread tracks a front tire tread, and even more specifically for a tire/vehicle system where the wheels are cambered.
2. Description of the Prior Art
In automotive vehicles, proper traction between the tire and the road surface is necessary for effective operation of the vehicle. Under certain weather conditions, such as rain, moisture or water can be deposited on the road surface and tire traction can be impaired. For example, a vehicle traveling on a rain-soaked road surface at high speed can "hydroplane" and the tires of the vehicle can lose contact with the road surface altogether. For this reason, it is desirable that tires be designed to channel water away from the footprint of the tire, to improve contact between the tire and road surface. U. S. Pat. No. 5,176,766 discloses a tire tread designed to provide good traction, especially on road surfaces covered with water.
Four-wheeled vehicles are usually fitted with identical tires at all four wheel positions, even though the operating conditions and performance requirements at each wheel may be different. For example, the functions necessarily performed by each tire, such as steering, load bearing, and transmitting driving torque from the engine to the road surface, are usually different at each wheel position.
Some tire designers have sought to maximize vehicle performance by tuning each tire to its respective wheel position. German Patent 1,480,962 discloses a front and rear tire combination in which the compound in the front tire is different from that in the rear tire, the combination designed to improve treadwear. German Patent 2,536,470 discloses a front and rear tire combination in which the tread pattern on the front tire is varied slightly from the tread pattern on the rear tire to limit the noise generated by the combination. Japanese Patent 58-164360 discloses a front and rear tire combination in which the tread pattern of the front tire differs from that of the rear tire in order to maximize the cornering characteristics of the vehicle. U.S. Pat. No. 4,984,616 discloses an automotive tire/vehicle system mainly for use on dry surfaces.
The present invention relates to a vehicle and tire system designed to improve wet traction.